#!/usr/bin/env lua

function system(command)
    local fd = io.popen(command, "r")
    string = fd:read("*all")
    fd:close()
    return (string.gsub(string, "\n$", ""))
end

amppath = os.getenv("AMPROOT") or error("AMPROOT not defined")
print((string.gsub(arg[1] or system("pwd"), "^"..amppath, "")))